SOME OF YOUR VEHICLES MAY HAVE BEEN ALTERED BY PREVIOUS OWNERS.

Here are some original wiring diagrams and images that may help you return it to the correct state. These are typical of the ignition circuits on OPUS equipped V12's. Many early systems may have been changed by dealers/service agents to a later system. This was an attempt to cure the problems Jaguar had with the OPUS ignition system. Consequently, you may have either early colour-banded black wiring or the later self-coloured wiring. To print these pages, it's best to save a .pdf version to your computer here If you do not have the free Adobe Acrobat .pdf reader, download it from here

Early type wiring diagram:

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EARLY TYPE ALL-BLACK WIRING.
NOTE SMALL COLOUR CODE BANDS ON WIRES!
(These are often hidden under white rubbery material on original circuit boards)
Be careful not to lose any bands or overlook any of the Black Bands on Black wires (difficult to spot).
Later type had self-coloured wires. (See below)

 

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Later type wiring diagram:

IMPORTANT NOTE: The wiring diagram shows two WU wires to the ballast resistor pack.
Close examination will show that the conventional WU, i.e. the one which is white with a straight blue stripe, is the one supplying power from the starter relay
( # 194 on the wiring diagram below). This goes to the "START" position.
The wire for the tachometer is the other WU, and is the one in which the blue stripe SPIRALS on the white. It may also be White/Slate instead of White/Blue.
Remember, your vehicle may only have five wires going into the amplifier and it is best to keep it this way. The tachometer may have been converted to run direct from the coil.

 

 

 

 

Below is a section from XJ12 SII Wiring diagram (with key below) showing relevant details. Other OPUS equipped vehicles will be similar.

 

 

 

 

Early type OPUS from V12 E-type. NOTE: Red coloured PC board compared to later type green board

 

Later type OPUS from XJ-S showing self-coloured wires NOTE: Lack of White/Blue wire due to different Tachometer driving arrangement.

 

 

 

 

Photo of Starter Solenoid/Ballast Coil Relay from XJ12 SII. Again, other vehicles will be similar.

 

 

 

 

 

Typical Ballast Resistor Pack with Coil bolted over top. NOTE: inputs stamped on casing - SII XJ12. In this photo, wiring to coil is NOT original, however the white/blue-spiral wire for the tachometer is typical. Later wiring harnesses may substitute this wire with white/slate.

WE WOULD WELCOME PHOTOS, DIAGRAMS, NOTES, ETC., OF ANY INSTALLATION YOU HAVE THAT MIGHT HELP OUR CUSTOMERS IN THE FUTURE.

 

MORE ON COLOUR CODES

British vehicles used colour coded wiring to help identify various circuits employed. This is from BS-AU7a 1983 Colour Code for Vehicle Wiring, from the British Standards Institution.

(These colour codes may not be totally applicable to older cars. However, the tables are a pretty good guide).